Answer:
My sister, who eats cookies for breakfast, weighs 100 pounds.
Explanation:
The first think I see is that the first letter is not capitalized. So capitalize that. (1) next, I saw that the sentence doesn't make sense. "My sister who eats cookies for breakfast weight 100 pounds"
Add a comma after 'sister' so the reader knows to pause. (2) Then, add a comma after 'breakfast' so its proper english. (3)
After, use weight correctly. 'Weight' should be 'weighs.' (4) And then, finally add a period.
